Cluster Node Windows service pack version does not match first node

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at https://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2009-09-23

The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine the Microsoft Windows® service pack version installed on each node in the cluster:

HKEY_LOCAL_MACHINE\Cluster\Nodes\<Node Number>\CSDVersion

If the Exchange Server Analyzer finds the value for CSDVersion on the second or subsequent node in the Exchange cluster different from the value for CSDVersion on the first node in the Exchange cluster, an error is displayed.

This error indicates that the nodes in this Exchange cluster are not running the same level of Windows service pack. It is recommended as a best practice that all nodes in an Exchange cluster run the same level of operating system and service pack.

To resolve this problem, you must upgrade all nodes to the same operating system and service pack. To minimize downtime, you can perform a rolling upgrade of your cluster.

For information about alternative procedures, see "Alternatives to rolling upgrades" (https://go.microsoft.com/fwlink/?linkid=34289).